• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.310-320
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• 2009

In this paper, we estimate area-averaged solution of peening residual stress using a 3-D multi-impact symmetry-cell FE model. The symmetry-cell model includes factors reflecting peening phenomena and plastic shot. Area-averaged solution is much closer to XRD experimental solution than 4-node-averaged solution in plastic shot FE model. We then obtain FE Almen saturation curve corresponding to experimental Almen curve based on area-averaged solution. Using the curve, we obtain FE area-averaged solution in major peening materials, and compare the FE solution with experimental solution. In peening materials, surface, maximum compressive residual stress and deformation depth reach experimental solutions. Thus, FE Almen curve is useful for estimation of residual stress solution and could improve the efficiency of peening process. Consequently, it is confirmed that concept of area-averaged solution is the realistic analytical method for evaluation of peening residual stress.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.546-549
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• 2011

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.337-338
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• 2014

본 논문에서는 배터리 셀 간의 빠른 전하 균일화를 위한 새로운 셀 밸런싱 회로를 제안한다. 대칭적인 다권선 변압기를 이용하는 밸런싱 회로의 경우 셀들 간의 밸런싱 전류의 크기가 회로 내부 저항 및 변압기의 누설 인덕턴스에 의해 크게 제약 받고, 배터리 셀 간의 밸런싱이 이루어짐에 따라 충방전 전류가 감소한다는 단점이 있다. 본 논문에서는 보조 회로를 이용하여 밸런싱 전류를 부스트 업 시켜 빠르게 셀 간의 전하 밸런싱을 맞추어주는 회로를 제안한다. 이를 통해 회로 내부 저항의 영향을 줄이고 일정한 충방전 전류를 흘려보냄으로 빠르게 셀 전하들의 밸런싱을 맞출 수 있다.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.196-201
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• 2013

In this paper, a dual-mode balanced filter with symmetric coupled composite right/left-handed transmission line is introduced. Unlike the other symmetric structure, this configuration has the ability to operate under both common- and differential-mode excitation. These properties are achievable through providing physical short circuit by means of ground vias at the center of each unit-cell along the symmetry plane of the structure. Because the CRLH unit-cells are operated under both common- and differential-mode excitation, we implemented a balanced filter using these properties. To validity these features, a five-cell four port coupled CRLH-TL is simulated, fabricated and measured and the obtained performances agree with the simulation results under both common- and differential-mode excitation.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.1
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• pp.92-96
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• 2003

본 논문에서는 비대칭 터보부호를 사용 무선 ATM환경에서 ATM셀을 전송할 때 비트 오류확률, 셀 손실확률을 대칭 터보부호와 비교하였다. 일반적으로 터보부호기는 동일한 재귀 컨벌루션코드(Resursive Systematic Convolution Code)로 구성된다. 비대칭 터보부호와 대칭적 터보부호를 비교하기 위한 생성다항식을 Primitive Polynomial과 Non-Primitive Polynomial 의 4가지 조합을 고려하여 시뮬레이션을 수행하였다. Feedback 다항식이 Primitive 다항식인 사용된 터보부호기가 Non-Primitive다항식이 사용된 터보부호기와 비교하여 1.2dB이상 성능 향상을 보였고, Primitive Polynomial과 Non-Primitive Polynomial이 같이 사용된 비대칭 터보부호기는 Non-Primitive Polynomial이 사용된 대칭 터보부호기와 비교하여 0.7dB 성능 향상을 보였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.318-324
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• 2011

In this paper, three coordinated random beamforming (CRBF) schemes are analyzed in a two-cell symmetric interference channel. A simple partial coordination of RBF with base station selection (BSS) is shown to achieve the same average sum rate performance of CRBF with joint encoding (JE). To improve the sum rate performance further, we also propose a transmission mode selection (TMS) between the BSS and JE which is shown to have additional sum rate gain for the large number of users. Simulation results verify the eectiveness of the proposed CRBF schemes and accuracy of the proposed analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1105-1112
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• 2020

One-dimensional 3-neighborhood Cellular Automata (CA)-based pseudo-random number generators are widely applied in generating test patterns to evaluate system performance and generating key sequence generators in cryptographic systems. In this paper, in order to design a CA-based key sequence generator that can generate more complex and confusing sequences, we study a one-dimensional symmetric 5-neighborhood CA that expands to five neighbors affecting the state transition of each cell. In particular, we propose an n-cell one-dimensional symmetric 5-neighborhood CA synthesis algorithm using the algebraic method that uses the Krylov matrix and the one-dimensional 90/150 CA synthesis algorithm proposed by Cho et al. [6].

• 대한공업교육학회지
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• v.33 no.2
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• pp.300-311
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• 2008

This study investigates the natural convection of air(Pr=0.7) between two walls having a small- wave- number sinusoidal temperature distributions with a phase difference. The wave number and the phase difference of wall temperatures are k=0.5 and ㄱ/2, respectively. In the conduction-dominated regime at small Rayleigh number, two slightly inclined cells are formed over one wave length. At higher Rayleigh number, however, multicellular convection occurs in thermally unstable region. A spatial symmetry is intermittently broken in the transient period at the Rayleigh number near the critical value. The steady-state flows always satisfy the spatial symmetry. A steep increase of Nusselt number occurs near the Rayleigh number at which transition of flow pattern occurs.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.11-18
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• 1997

By utilizing the technique to monitor the DC cell node voltages through circuit simulation, degradation of the static read operating margin In high load-resistor SRAM cell was examined, which is caused by parasitic resistances and transistor asymmetries in this cell structure. By selectively adding the parasitic resistances to an ideal cell, the influence of each parasitic resistance on the operating margin was examined, and then the cases with parasitic resistances in pairs were also examined. By selectively changing the channel width of cell transistors to generate cell asymmetry, the influence of cell asymmetry on the operating margin was also examined. Analyses on the operating margins were performed by comparing the supply voltage values at which two cell node voltages merge to a single value and the differences of cell node voltages at VDD=5V in the simulated node voltage characteristics. By determining the parasitic resistances and the transistor asymmetries which give the most serious effect on the static read-operation of SRAM cell from this analysis based on circuit simulated, a criteria was provided, which can be referred in the design of new SRAM cell structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1885-1894
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• 1999

The higher mode cutoff frequencies in Crawford TEM cells computed by the Galerkin method(GM) describe in this paper. The authors also report the half mode boundaries to solve not only the cut-off frequencies of symmetric TEM cells and those of asymmetric TEM cells. It is shown that the measured resonant frequencies of the present symmetric TEM cells and a designed asymmetric TEM cell are agreed with the calculated results.